Gaseous fuel powered engines are common in many applications. For example, the engine of an engine generator set (genset) can be powered by natural gas or another gaseous fuel. Natural gas may be more abundant and, therefore, less expensive than alternative fuels. Natural gas may also burn cleaner in some applications. During power outages, natural gas may be readily supplied to genset engines for extended periods of time via a direct connection to a gas utility, or over limited periods of time and in mobile applications via one or more associated storage tanks.
One problem associated with gaseous fuel powered engines is that a greater amount of time may be needed to initially start gaseous fuel powered engines as compared to engines powered by other types of fuel, such as diesel fuel. In particular, whereas diesel fuel may be supplied directly to combustion chambers of the engine, gaseous fuel may normally be supplied to the engine's intake system upstream of an associated compressor, so that the fuel needs to traverse a substantial portion of the intake system before reaching a combustion chamber of the engine. This may be problematic for gaseous fuel powered engines that drive gensets, where it may be desirable to minimize the amount of time between the loss of grid power and the provision of backup power, and/or where regulatory standards on genset startup times are applicable.
One example of a system for starting a gaseous powered engine is disclosed in U.S. Pat. No. 5,713,340 (the '340 patent) that issued to Vandenberghe et al. on Feb. 3, 1998. In particular, the '340 patent discloses a lower-pressure fuel source and a higher-pressure fuel source connected to an engine. The system determines whether the engine is being started based on the engine's speed, and delivers higher-pressure fuel directly to the engine from the higher-pressure fuel source. After the engine has started and a proper air/fuel ratio is achieved, the higher-pressure fuel supplied to the engine is reduced, and a supply of lower-pressure fuel is delivered to the engine from the lower-pressure fuel source during steady state operation. In this arrangement, the system of the '340 patent includes both a low pressure fuel source and a high pressure fuel supply. The starting ability of the system of the '340 patent may be limited by an amount of higher-pressure fuel stored within the higher-pressure fuel source, and a need to replenish the higher-pressure fuel source.